Magnetic core construction



Nov. 7, 1961 J. w. RICHARDSON, JR 3,008,106

MAGNETIC CORE CONSTRUCTION 2. Sheets-Sheet 1 Filed Dec. 3, 1957 INVENTOR Aosevu N- R\cHARDsoN, R

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ATTORNEY Nov. 7, 1961 J. w. RICHARDSON, JR 3,008,106

MAGNETIC CORE CONSTRUCTION Filed Dec. 3, 195'? 2 Sheis-Sheet 2 INVEN TOR.

n'rronnlsv mcnnevso NQR 3,008,106 MAGNETIC CURE CUNSTRUCTIQN Joseph W. Richardson, Jra, Horsham, Pa, assignor, by mesne assignments, to H. K. Porter Company, inc, Pittsburgh, Pin, a corporation of Delaware Filed Dec. 3, 1957, Ser. No. 7titl,425 6 Claims. ((31. 336-) This invention reiates generally to electro-magnetic induction apparatus and more particularly to improved threehase transformers, reactors and like apparatus employing conductive coil structures.

Among the principal objects of the present invention is to provide a delta arrangement of three conductive coils assembled in a three-phase magnetic core structure, in which a center conductive coil is supported by a pair of laterally spaced conductive coils with the opposite side legs of the center conductive coil respectively disposed directly above the inner side legs of the laterally spaced conductive coils. Each conductive coil has a window for the reception of the legs of the associated magnetic core structures, the latter being relatively so arranged as to provide three vertically extending legs of cross sectional areas which respectively generally correspond to the shape of the coil windows. The reduction in overall width of the conductive coils resulting from the delta arrangement thereof provides an important space-saving advantage.

Still another important object of the present invention is to provide three conductive coils in a delta arrangement with one coii for each phase of a three-phase electrical system, the delta configuration being such as to provide the several conductive coils with closely spaced parallel magnetic axes.

The magnetic cores for the delta arrangement of the conductive coils are themselves disposed in a co-planar arrangement wherein one outer core surrounds and embraces two inner cores in such manner as to provide the composite core structure with three parallel legs which respectively pass through the windows of the deltaarranged conductive coils. The resultant assembly of magnetic core and conductive coils effects a considerable reduction in the outside dimensions thereof, particularly in the overall horizontal length of the delta-assembled coils.

Stiil another object of the present invention is to provide a delta arrangement of three conductive coils in a three-phase magnetic core structure comprising three cores two of which are disposed in side by side relation and nested within the third core to provide a co-planar arrangement thereof having a pair of vertically elongated, laterally spaced coil-receiving windows, the three conductive coils being disposed in delta stacked relation with their vertically aligned sections respectively projecting through the spaced elongated windows of the core structure in such manner that the top-most coil of the delta stack extends about the center leg while the two bottom coils hereof respectively extend about the outer legs of the core structure, whereby to provide a compact three-phase transformer structure affording an exceedingly high spacesaving factor without sacrifice in overall operating efficiency thereof.

Other objects and advantages of the present invention will be apparent hereinafter, itbeing understood that the present invention consists in the combination, construction, location and relative arrangement of parts, all as will be described more fully hereinafter, as shown in the accompanying drawings and as finally pointed out in the appended claims,

In the accompanying drawings which are illustrative of the principles of the present invention:

3,008,106 Patented Nov. 7, 1961 FIGURE 1 is a perspective view of an electro magnetic induction apparatus, in this case a three-phase transformer, having a delta arrangement of conductive coils assembled in a three-phase core structure in accordance with the present invention;

FIGURE 2 is a top plan view of the three-phase transformer;

FIGURE 3 is a side elevational View of the three-phase transformer as viewed from the line 33 of FIGURE 2; and

FIGURE 4 is a cross sectional view of the three-phase coil structure as taken along the line 44 of FIGURE 2, the associated core structure being shown in elevation.

Referring now more particularly to the drawings, it will be observed that the three pre-formed electrically conductive coils 10, 11 and 12 arranged in the delta configuration of the present invention are shown in association with three magnetic cores 13, 14 and 15 of a three-phase electro magnetic apparatus, for example, a three-phase transformer.

The several magnetic coil 1t 11 and 12, which may be of any desired conventional construction, are relatively arranged as shown with two of the coils 10 and 11 spaced laterally apart and commonly supporting thereon the third coil 12, their relative spacing being preferably such that the inner side section lilo of coil 10 is vertically aligned with one side section 12a of coil 12 while the inner side section 11:: of coil 11 is vertically aligned with the opposite side section 12b of coil 12. The coils 10, 11 and 12 are generally each of the same cross section and configuration and thus by stacking them in delta arrangement as shown and described, they conjointly provide three uniformly spaced core-receiving windows 16, 17 and 13 each of the same general shape and size, these windows being confined between two spaced parallel vertical planes extending lengthwise of the delta stacked coils.

The vertical axis of the several windows of the stacked coils extend parallel to one another and of course are spaced equally apart.

The associated magnetic core structures 13, 14 and 15 are each preferably of the laminated construction shown and described in my co-pending application, Serial No. 657,530, filed May 7, 1957, the several laminae 19 of each of the inner cores 14 and 15 being formed of individual strips of magnetic material suitably cut to length and spirally wound to a shape corresponding to the cross sectional shape of the vertically aligned winding leg sections of the delta stacked coils, while the several laminae 2d of the outer core 13, also formed of individual strips of magnetic material suitably cut to length, are spirally wound to a shape corresponding generally to the external configuration of the combined inner cores 14 and 15. The several spirally wound laminae of each core, which are permanently set to shape and stress-relieved by suitable heat treating, are readily assembled with and about the delta stacked conductive coils 10, 11 and 12 by successively threading each lamination through the windows 16, 17 and 18 of the coils.

In this latter connection it will be noted that the laminae of the magnetic core 14 are threaded through the windows it: and 17 of the coils 10 and 12 so that said core 14 is commonly associated with the coils 10 and 12, while the laminae of the magnetic core 15 are threaded through the windows 17 and 18 of the coils 11 and 12 to provide the latter with their common core 15. Thereafter, the laminae of the outermost core 13 are successively threaded through the coil windows 16 and 18 so that the core 13 is common to the conductive coils 10 and 11.

It will be noted that the delta arrangement of the conductive coil windings in association with the magnetic core structures, as shown and described, provides in effect a central shell type transformer assembly for one phase of the transformer and a pair of laterally spaced core type transformer assemblies for the remaining two phases, in each of which assembly the magnetic core structures are closely related to their respective coil windings. Moreover, the three-phase transformer, considered as a whole, is of an overall longitudinal dimension considerably less than that which would be obtained by disposing the same capacity conductive coil winding in a common horizontal plane, thereby effecting a considerable and important reduction in the horizontal cross sectional area of the transformer.

'I he conductive coil side legs, about which the magnetic cores are applied, may be of any desired non-circular shape, preferably of a quadrangular cross section, either square or rectangular, having their edges and corners rounded off. The magnetic core structures respectively associated with the several conductive coils are of cross sectional shapes generally corresponding to the shape of the coil windows so as to provide compact assemblies of coil windings and magnetic cores. It will be understood of course that each of the coil windings lit, 11 and 12 include both a primary and a secondary coil. It will be understood further that while the core structures are preferably formed of concentrically stacked laminae as described in my co-pending application Serial No. 657,530 hereinbefore mentioned, the present invention is not limited to any particular construction of magnetic core for each of the cores assembled in delta arrangement in accordance with the present invention. Also, the present invention is susceptible of various other changes and modifications which may be made from time to time without departing from the general principles or real spirit of the invention and accordingly it is intended to claim the same broadly, as well as specifically, as indicated by the appended claims.

What is claimed as new and useful is:

l. A three-phase electromagnetic induction apparatus comprising three conductive-winding structures respectively adapted to be connected to the several phases of a,

three-phase electrical system, two of said winding structures being disposed in laterally spaced co-planar relation and the third in vertically offset relation to said two coplanar structures, each of said winding structures having a window for accommodation of magnetic core material, which window in each instance is defined by a pair of spaced parallel side winding legs, the winding legs of each winding structure being substantially square in crosssection, the parallel side winding legs of the third winding structure being each vertically alined with one leg of an adjoining one of the two coplanar winding structures whereby to provide a closely coupled arrangement of the three winding structures with their magnetic axes in parallel relation and equally spaced apart a distance approximately equal to the combined width of a window opening and one side winding leg of a winding structure, and three magnetic cores respectively associated with said winding structures, said cores being assembled in co-planar relation with two of them in side by side arrangement and externally embraced by the third, the inner two cores of the assembly being respectively provided with openings which are vertically elongated and of a cross-sectional area corresponding to the combined cross-sectional area of the vertically alined side legs of an adjoining pair of said winding structures.

2. In a three-phase electromagnetic induction apparatus as defined in claim 1 wherein one of the inner two of said magnetic cores extends about the vertically alined winding legs and through the windows of one pair of said vertically offset winding structures, the other of said inner cores extends about the vertically alined Winding legs and through the windows of the other pair of said vertically offset winding structures, and the external third core extends about the outside of said third winding structure and through the windows of the laterally spaced, coplanar pair of said winding structures.

3. A three-phase electromagnetic induction apparatus comprising three conductive-winding structures respectively adapted to be connected to the several phases of a three-phase electrical system, and three magnetic core structures associated with said winding structures, each of said core structures being formed of a plurality of superimposed, concentrically wound strips of magnetic sheet material, said core structures being assembled in coplanar relation with two of them in side by side relation and embraced externally by the third, the winding legs of each winding structure being substantially square in crosssection, the centermost winding structure being vertically disposed relatively to the two outermost winding structures with its opposite side winding legs in vertical alinement respectively with the two adjacent side winding legs of said outermost winding structures whereby to provide the winding structure assembly with core-receiving windows having parallel magnetic axes uniformly spaced apart a distance equal to the combined width of a window and thickness of one side winding leg of a conductive winding structure.

4. In a three-phase electromagnetic induction apparatus comprising three conductive-winding structures respectively adapted to be connected to the several phases of a three-phase electrical system, and three magnetic core structures associated with said winding structures, said winding structures being disposed in laterally spread relation with the centerrnost one vertically offset relatively to the outermost two thereof to provide the winding structure assembly with three core-receiving windows spaced apart by a distance not exceeding the width or thickness of a side leg of a winding structure.

5. In an apparatus as defined in claim 4, wherein each core-receiving window of the three winding structures accommodates two of the magnetic core structures, the first of said core structures passing through the windows of the two outermost winding structures, the second of said core structures passing through the window of one outermost winding structure as well as the window of the centermost winding structure, and the third of said core structures passing through the Window of the other outermost winding structure as well as through the window of the centermost winding structure.

6. in a three-phase electromagnetic induction apparatus, a magnetic core assembly comprising three core structures arranged in coplanar relation with two inner core structures disposed in side by side relation within and externally embraced by a third core structure, the core assembly being of substantially uniform width throughout, each inner core structure being provided with one of a pair of parallel extending vertically elongated, laterally spaced openings respectively adapted to accommodate therein conductive winding structures operatively associated with the core structures, each of said openings being of a cross sectional area sufficient to encompass the vertically alined winding legs of a closely related pair of conductive winding structures.

References Cited in the file of this patent UNITED STATES PATENTS 2,344,294 Evans Mar. 14, 1944 

